Process of coherently uniting plastic material to sheet metal



Obi-5, 1937. J, 5, m5 2,095,198

PROCESS OF GOHERENTLY UNITING PLASTIC MATERIAL TO SHEET METAL Filed Jan. 16, 1936' FIG-2 JAMES S. REID ATTORNEY) metal strip. is cooled sufficiently to effect corisurroundedb the cooling chamber l3a of a coolmeans of a worm 25 arranged within said conduit l2 into a suitable cooling unit it in which the pump ill until it emerges into the extrudingchamber 2i and that the cooling effect of the traction thereof, as indicated at C, Fig. 3. Berefrigerant is also maintained until such emercause of cooling fins in with which said conduit gence occurs. Although the operation of the is externally provided, the metal strip receives worm 25 effects a heating of'the plastic material some preliminary cooling before it enters a guide before it reaches the extruding chamber, additube ll of the cooling unit, said guide tube being tional heating means for such plastic material may be utilized, if necessary or desirable. in ube l4 withwhich the guiwgx- After the plastic-coated metal strip is drawn tensive and of which it may be an integr -rt,\' fmmt he%iguding unit, it is permitted to cool to as shown. Through the cooling tube chamber normal e refrigeratin'g device i5, suitablyconnected to said'cooling chamber by supply and return pipes I6. Inasmuch as the guide tube ll communicates with the conduit 12 which in turn communicates with the heating chamber 90, said Although the present invention is particularly guide tube and said conduit are maintained, like applicable to the coating of steel sheets or strips said heating chamber, in an evacuated condition with rubber, it is to be understood that said inby operation of the vacuum pump ill. The coolvention is not limited thereto, as any suitable ing fluid,or refrigerant circulated through the plastic material or composition may be used for cooling chamber l3a is of such a nature that the such coating purposes, such as gutta-percha, ozometal strip, as it passes through the guide tube kerite, asphalt or other bituminous material. It I I surrounded by suchcooling chamber, is mainis also to be understood that if the surface of tained substantially below normal temperatures, the metal is free of impurities, such as grease and preferably close to or below 0 C., to effect the dedirt, the cleaning step may be omitted. sired contraction of such metal strip, as will be To those skilled in the art, many modifications readily understood. and widely different embodiments and applica- From the cooling unit, the cooled and contions of the invention will suggest themselves, tracted metal strip is drawn into an extruding without departing from the spirit and scope. of unit 20, within the chamber 2i of which is a. holthis invention, the present disclosure being merelow cone-shaped element 22 into which pro- 13' illustrative. ject forward ends of the cooling tube i4 and the What I claim is: 1 v guide tube l'i therewithin. The apex of the cone- 1. The process of coherently uniting hot plastic shaped element 22 terminates adjacent the discomposition to metal, which comprises heating charge die member 23 of the extruding unit and the metal, with consequent expansion thereof, is provided with a suitable exit slot for the metal subjecting the heated metal to a vacuum eifect strip I, said exit slot being in alignment with the while it is in such expanded condition, with condischarge opening of the die member 23, as sequent removal of air, moisture, etc., from the shown. I spaces or crevices of the metal, cooling the ex- The plastic material, such as rubber, which is Banded metal While 18 Still being Subjected to to be coherently united with the metal strip l, a va uum effe t, w th cons qu t contraction of enters the extruding chamber 2| through a con- Said-metal. and pp y to the contracted w duit 2| a connected to a suitable hopper 2|, the the i; plastic composition without p sin! t plastic material being forced through said conmetal to the atmosphere, w consequent duit from said hopper into said chamber by ta i 01 said Plastic composition to 88 61 2. The process of coherently uniting a hot plastic composition to metal, which comprises heating the metal in an evacuated chamber, with consequent expansion of the metal, and the removal of air, moisture, etc., from the spaces or crevices thereof, cooling the heated metal in an evacuated chamber, with consequent contraction of the metal, and applying to the cooled metal the hot plastic composition without exposing the metal to the atmosphere, with consequent coherent uniting of said plastlclcomposition to'said metal.

3. The process of coherently uniting hot plastic rubber to metal, which comprises heating the coated metal strip is subjected to a vulcanization operation to cure the rubber, as will be readily understood.

and driven by the rotation of a pulley 26 associated therewith and operatively connected to any suitable source of power,

The cooled and contracted metal strip contacts the hot rubber or other plastic material upon emerging from the cone-shaped projection 22 within the extruding chamber 2], and the effect of suchcontact is the sudden expansion of the metal strip, the consequent sudden opening up of the spaces and crevices thereof, and the resultinguniting, coherently, of the rubberor other plastic material with the metal strip. The coherent uniting of the. plastic material and the metal is believed to be due, in part, to the vacuum metal, with consequent expansion thereof, subeffect which'is produced in each ,of the minute jecting such heated metal to a vacuum effect, spaces orcrevices of the metal by the sudden with consequent removal of air, moisture, etc., expansion of the crystals thereof in the presence from the spaces or crevices of the metal, cooling of the heated plastic material, the effect being the expanded metal while it is still being subto draw the plastic material by suction into such jected to a vacuum effect, with consequent conspaces or crevices. It is to be understood, howtraction of the metal, applying hot plastic rubber ever, that the present invention is not to be to said cooled and contracted metal, with conselimited by the aforesaid belief concerning the quent coherent uniting of said rubber to said coherent character of the uniting of the plastic metal, and subjecting the rubber coherently material to the metal strip, as such coherent re- ,united to said metal to a vulcanizing operation. sults may be, due wholly or in part to othe 4. The process of coherently uniting hot plastic causes, composition to .metal which comprises heating It is to be noted that the metal strip is subthe metal in a chamber to expand it, evacuating jected to the evacuating effect of the vacuum the chamber to remove air, moisture, etc. from eratu lthough it may be sub- I l3a is circulated a suitable refrigerant from a jected to other treatmen, esimd. For instance, if the plastic material is raw rmthe\ the surface and spaces or crevices of the metal, cooling the metal to a temperature substantially below normal room temperature to effect a contraction of the metal, and then applying a hot 5 plastic composition to the cooled contracted metal without exposing it to the atmosphere, thereby causing a coherent uniting or the plastic composition to said metal. Y

5. The process of coherently uniting a hot plas- 10 tic, composition to a ferrous metal which comprises heating the metal in a chamber to a temperature below the recalescence point to expand it while evacuating the chamber to remove air, moisture, etc.'from the surface of the metal and 15 from the pores or crevices between the crystalline,

structure, cooling the metal to a temperature substantially below normal room temperature to effeet a. contraction of the metal while maintaining a vacuum around the metal, and then apply- 3 ing a hot plastic composition to the cooled contracted metal without exposing the metal to the atmosphere, thereby causing a coherent uniting of the plastic composition to the metal surface.

6. The process of coherently uniting a hot plastic'composition to a metal which comprises continuously passing a strip of metal through a heated chamber while evacuating the chamber to expand the metal and remove moisture and gases from the surface and between the pores or crevices of the metal, passing the metal through a communicating evacuated chamber and cooling the metal to a temperature substantially below room temperature to contract the metal, and then passing the cooled contracted metal through a hot plastic composition to expand the metal and cause the hotplastic composition to become coherently united to the metal surface.

. JAMES S. REID. 

